1. Field of the Invention
The present invention relates to a windscreen wiper, and more particularly, to a soft wiper that makes use of two pairs of built-in type resilient pieces to provide the softness, resiliency, and strength which required by the wiper strip for closely contacting with the windscreen surface.
2. Description of the Prior Art
FIG. 1 is a schematic structural diagram of the multi-pivot windscreen wiper of the prior art. As shown in FIG. 1, the windscreen wiper structure of the prior art makes use of a wiper arm (10) to generate reciprocating wiping motion.
Such a windscreen wiper in the prior art, includes a primary carrier (12) to drive a plurality of auxiliary carriers (13) thereby to uniformly transfer and distribute a biasing force yielding from the spring which loaded in the wiper arm (10) and acting on the car windscreen. One can refer to some improvements of this kind of conventional wipers disclosed by the U.S. patents such as U.S. Pat. No. 5,493,750, U.S. Pat. No. 5,598,603, or U.S. Pat. No. 6,754,933 etc.
A significant problem is existed in the windscreen wiper with the auxiliary carriers while used in a frigid-zone where the rain and ice may freeze between the carriers and affects the motion of the wiper. Therefore, there is a further design of the wiper appeared as shown in FIG. 2.
As shown in FIG. 2, another conventional wiper which is driven by a wiper arm (20) comprises a wiper strip (21) fixed to an intermediate portion of a resilient piece (22) by a pivotal connector (23).
The pivotal connector (23) connected with the wiper arm (20) and used to transmit the biasing force from the wiper arm (20) through the resilient piece (22) thereby acting on the windscreen for wiping the rain.
The conventional windscreen wiper may have another problem that the distal end thereof may be dragged by a friction force while wiping on the windscreen, this friction force shall act on the pivotal connector (23) and cause the whole wipe blade distortion and vibration, the longer the wiper blade, the larger the problem is.
As a result, some unpleasant jerks may occur while the friction force acting on both ends of the wiper. There are many alternative designs of this windscreen wiper, and one can refer to U.S. Pat. No. 6,687,948 and U.S. Pat. No. 6,799,348.
As shown in FIG. 3, another conventional wiper includes a pivotal connector (31), a resilient piece (32), a wiper strip (33), a pair of protecting covers (34), and a pair of end caps (35) wherein the outer intermediate portion of the resilient piece (32) secured to the inner edge of the protecting covers (34).
The resilient piece (32) is formed with a closed groove (321) positioned along the central line thereof and a passage extending through the pivotal connector (31). One end of the closed groove (321) further formed with a wider opening (322) that allows the wiper strip (33) to get in and pass therethrough.
To assemble such a wiper, one should insert the wiper strip (33) through the hole (322) and the passage thereby to advance to another end of the groove (321). Finally, the one should put on the end caps (35) to secure at the both ends of the wiper.
FIG. 4 is a schematic diagram showing the distal end of a traditional wiper deformed in a non-smoothly wiping on a windscreen. As shown in FIG. 4, since the conventional wiper (40) driven by a pivotal connector (41) to drive the resilient piece (42), the wiper is dragged by the friction force from the screen this would yield a torque acting on the whole sectional-width (43) thereof.
The torque causes the deformation at the distal end of the wiper strip (33). Further, once the friction force drags the wiper unevenly, the wiper would jerk and fail to clean the rain clearly. It would become worse if the wiper is relative longer but lacks sufficient strength to lower the jerk.